Exosomes Derived from Heat-shocked Tumor Cells Promote In vitro Maturation of Bone Marrow-derived Dendritic Cells.

Dendritic cells (DCs), professional antigen-presenting cells that process and deliver antigens using MHC II/I molecules, can be enhanced in numerous ways.  Exosomes derived from heat-shocked tumor cells (HS-TEXs) contain high amounts of heat-shock proteins (HSPs). HSPs, as chaperons, can induce DC maturation. This study aimed to investigate whether HS-TEXs can promote DC maturation. To generate DC, bone marrow-derived cells were treated with Interleukin-4 and GM-CSF. Exosomes were isolated from heat-treated CT-26 cells. The expression level of HSP in exosomes was checked by western blot and the increase in the expression of this protein was observed. Then, HS-TEXs were co-cultured with iDCs to determine DC maturity, and then DCs were co-cultured with lymphocytes to determine DC activity. Our results showed that  DCs treated with HS-TEXs express high levels of molecules involved in DC maturation and function including MHCII, CD40, CD83, and CD86. HS-TEXs caused phenotypic and functional maturation of DCs. In addition, flow cytometric results reflected a higher proliferative response of lymphocytes in the iDC / Tex + HSP group. HS-TEXs could be used as a strategy to improve DC maturation and activation.

Regulation of the Th17/Treg balance by human umbilical cord mesenchymal stem cell-derived exosomes protects against acute experimental colitis.

Increasing evidence suggests that mesenchymal stem cells (MSCs) have immunosuppressive properties mediated by MSC-derived small extracellular vesicles (sEV). Exosomes are small extracellular vesicles that contain components that regulate immune cell function. We investigated the immunomodulatory effects of MSC-derived Exosome (MSC-Exo) on the severity of colitis using the dextran sulfate sodium (DSS)-induced colitis model. Exosomes were administrated intraperitoneally. Daily changes in body weight, stool consistency, and bleeding were assessed to determine the impact of MSC-Exos on colitis. Several measurements were taken, including the colon weight, length, and histological analysis of the colon tissues. The percentage of regulatory T cells and IL-10, TGF-ß, IL-17, TNF-α, and IFN-γ levels were calculated in the mesenteric lymph node (MLN) and spleen. The results showed MSC-Exos improved clinical manifestations of colitis. Colon macroscopic and histological observations also showed improvement in tissue destruction. The results illustrated that MSC-Exos might attenuate colitis by regulating Treg/Th17 balance, increasing anti-inflammatory, and decreasing pro-inflammatory cytokines expression. As a result, MSC-Exos could be used as an immunomodulatory approach to treating bowel inflammation.

Adipose-derived mesenchymal stem cell-secreted exosome alleviates dextran sulfate sodium-induced acute colitis by Treg cell induction and inflammatory cytokine reduction.

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is an inflammatory condition that results in gastrointestinal tract damage. Various factors, including environmental and genetic agents, disrupt the function of the intestinal immune system that can lead to IBD. Mesenchymal stem cells (MSCs) display an immunoregulatory function and demonstrate regenerative potential by paracrine action. In this study, we evaluated the immunomodulatory effects of MSCs' derived exosomes in the acute form of dextran sulfate sodium (DSS)-induced colitis. Exosomes were isolated from adipose-derived MSCs. Acute colitis was induced by DSS. The exosome was used by intraperitoneal injection into mice with acute colitis. Stool consistency, body weight changes, bleeding severity, colon length, and weight were examined. At the experimental endpoint (Day 7), the changes in the colon tissue were evaluated. The level of cytokines of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), IL-4, IL-12, transforming growth factor-ß (TGF-ß) and, IL-10, and Treg cells percentage were assayed. Results showed that exosome administration diminished colon shortening, bodyweight loss, bleeding, and colon injury. The levels of IFN-γ, TNF-α, IL-12, and IL-17 were decreased, and the level of TGF-ß, IL-4, and IL-10 were increased in lymph node and spleen of mice treated with exosome.  Percentages of CD4+ CD25+ Foxp3+ Treg cells were grown in the lymph node and spleen of mice treated with exosomes. Overall, current data suggest that MSC-derived exosome could regulate the Treg population and improves inflammation in DSS-induced acute colitis.

Synergistic therapeutic effect of mesenchymal stem cells and tolerogenic dendritic cells in an acute colitis mouse model.

Cell-based therapy with tolerizing cells has been applied for the treatment of inflammatory bowel disease (IBD) in previous experimental and clinical studies with promising results. In the current study, we utilized the dextran sulfate sodium (DSS)-induced colitis model, to investigate if tolerogenic dendritic cell-mesenchymal stem cell (tDC-MSC) combination therapy can augment the therapeutic effects of single transplantation of each cell type. The effect of MSC and tDC co-transplantation on the severity of colitis was assessed by daily monitoring of body weight, stool consistency, and rectal bleeding, and compared with control groups. Moreover, the colon length, colon weight, myeloperoxidase (MPO) activity were measured and evaluated with histological analysis of colon tissues. The Treg cell percentage and cytokine levels in spleens and mesenteric lymph nodes (MLNs) were measured by flow cytometry and ELISA, respectively. The results showed co-transplantation of MSCs and tDCs was more effective in alleviating the clinical and histological manifestations of colitis than monotherapy, especially when compared with MSC alone. The protective effects of tDC-MSC were accompanied by the induction of Treg cells and increased the production of anti-inflammatory cytokines in spleens and mesenteric lymph nodes. Together, co-transplantation of MSCs and tDCs could be a promising and effective therapeutic approach in the treatment of IBD.

Cloning and Stable Expression of cDNA Coding For Platelet Endothelial Cell Adhesion Molecule -1 (PECAM-1, CD31) in NIH-3T3 Cell Line.

PURPOSE: PECAM-1 (CD31) is a glycoprotein expressed on endothelial and bone marrow precursor cells. It plays important roles in angiogenesis, maintenance and integration of the cytoskeleton and direction of leukocytes to the site of inflammation. We aimed to clone the cDNA coding for human CD31 from KG1a for further subcloning and expression in NIH-3T3 mouse cell line. METHODS: CD31 cDNA was cloned from KG1a cell line after total RNA extraction and cDNA synthesis. Pfu DNA polymerase-amplified specific band was ligated to pGEMT-easy vector and sub-cloned in pCMV6-Neo expression vector. After transfection of NIH-3T3 cells using 3 µg of recombinant construct and 6 µl of JetPEI transfection reagent, stable expression was obtained by selection of cells by G418 antibiotic and confirmed by surface flow cytometry. RESULTS: 2235 bp specific band was aligned completely to human CD31 reference sequence in NCBI database. Transient and stable expression of human CD31 on transfected NIH-3T3 mouse fibroblast cells was achieved (23% and 96%, respectively) as shown by flow cytometry. CONCLUSION: Due to murine origin of NIH-3T3 cell line, CD31-expressing NIH-3T3 cells could be useful as immunogen in production of diagnostic monoclonal antibodies against human CD31, with no need for purification of recombinant proteins.

Cloning and Expression of CD19, a Human B-Cell Marker in NIH-3T3 Cell Line.

BACKGROUND: CD19 is a pan B cell marker that is recognized as an attractive target for antibody-based therapy of B-cell disorders including autoimmune disease and hematological malignancies. The object of this study was to stably express the human CD19 antigen in the murine NIH-3T3 cell line aimed to be used as an immunogen in our future study. METHODS: Total RNA was extracted from Raji cells in which high expression of CD19 was confirmed by flow cytometry. Synthesized cDNA was used for CD19 gene amplification by conventional PCR method using Pfu DNA polymerase. PCR product was ligated to pGEM-T Easy vector and ligation mixture was transformed to DH5α competent bacteria. After blue/white selection, one positive white colony was subjected to plasmid extraction and direct sequencing. Then, CD19 cDNA was sub-cloned into pCMV6-Neo expression vector by double digestion using KpnI and HindIII enzymes. NIH-3T3 mouse fibroblast cell line was subsequently transfected by the construct using Jet-PEI transfection reagent. After 48 hours, surface expression of CD19 was confirmed by flow cytometry and stably transfected cells were selected by G418 antibiotic. RESULTS: Amplification of CD19 cDNA gave rise to 1701 bp amplicon confirmed by alignment to reference sequence in NCBI database. Flow cytometric analysis showed successful transient and stable expression of CD19 on NIH-3T3 cells (29 and 93%, respectively). CONCLUSION: Stable cell surface expression of human CD19 antigen in a murine NIH-3T3 cell line may develop a proper immunogene which raises specific anti-CD19 antibody production in the mice immunized sera.

Preparation of Proper Immunogen by Cloning and Stable Expression of cDNA coding for Human Hematopoietic Stem Cell Marker CD34 in NIH-3T3 Mouse Fibroblast Cell Line.

PURPOSE: Transmembrane CD34 glycoprotein is the most important marker for identification, isolation and enumeration of hematopoietic stem cells (HSCs). We aimed in this study to clone the cDNA coding for human CD34 from KG1a cell line and stably express in mouse fibroblast cell line NIH-3T3. Such artificial cell line could be useful as proper immunogen for production of mouse monoclonal antibodies. METHODS: CD34 cDNA was cloned from KG1a cell line after total RNA extraction and cDNA synthesis. Pfu DNA polymerase-amplified specific band was ligated to pGEMT-easy TA-cloning vector and sub-cloned in pCMV6-Neo expression vector. After transfection of NIH-3T3 cells using 3 µg of recombinant construct and 6 µl of JetPEI transfection reagent, stable expression was obtained by selection of cells by G418 antibiotic and confirmed by surface flow cytometry. RESULTS: 1158 bp specific band was aligned completely to reference sequence in NCBI database corresponding to long isoform of human CD34. Transient and stable expression of human CD34 on transfected NIH-3T3 mouse fibroblast cells was achieved (25% and 95%, respectively) as shown by flow cytometry. CONCLUSION: Cloning and stable expression of human CD34 cDNA was successfully performed and validated by standard flow cytometric analysis. Due to murine origin of NIH-3T3 cell line, CD34-expressing NIH-3T3 cells could be useful as immunogen in production of diagnostic monoclonal antibodies against human CD34. This approach could bypass the need for purification of recombinant proteins produced in eukaryotic expression systems.